1. Field of the Invention
This invention relates to a gamma correction device for an image sensing device or the like.
2. Description of the Related Art
Heretofore, to correct the non-linearity of the light emission characteristic of the luminescent material of a TV Braun tube, gamma correction has been made beforehand by an image sensing device, for example, on the basis of a gamma correction characteristic such as y=x.sup..gamma. and .gamma.=0.4 to 0.5 as shown in FIG. 1.
However, in the above-stated example of the conventional arrangement, the gamma correction characteristic is always fixed. Therefore, in the event of a very bright object, for example, the image of the object cannot be fully reproduced on the Braun tube and the arrangement tends to give a blank white part.
To solve this problem, there has been proposed a method of making white compressing correction as indicated with a broken line in FIG. 1. However, this method merely prevents bright image parts from becoming blank. According to this method, dark image parts or intermediate signal levels are apt to have an insufficient tone depending on the kind of the object. In cases where sunny and shady places commingle under sunlight within one and the same still picture, both black and white (dark and bright) parts become blank to give a picture which is not adequately appreciable by the human eye.